TABLE 1

Performance characteristics of the Escherichia coli sequence type 648 complex (STc648) PCR assay with 212 validation strains

LaboratoryNo. of isolatesAssay performance characteristicsa
STc648Non-STc648TotalSensitivity, % PPV (95% CI)Specificity, % NPV (95% CI)
11050b60100 (69–100)100 (93–100)
29143c152100 (66–100)100 (97.5–100)
Total19193212100 (82–100)100 (98–100)
  • a PPV, positive predictive value; NPV, negative predictive value; CI, confidence interval. PPV and NPV depend on the prevalence of STc648 in the population, so are not generalizable to other populations.

  • b STs represented (n = 50): 10, 12, 14, 23, 38, 43, 44, 46, 47, 48, 49, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 64, 66, 67, 68, 69, 70, 71, 73, 75, 84, 85, 86, 88, 127, 131, 141, 144, 167, 372, 393, 394, 405, 410, 550, 576, 598, 617, 618, and 3856.

  • c STs represented (n = 68): 38, 59, 62, 68, 104, 106, 117, 126, 131, 132, 135, 141, 144, 349, 354, 357, 362, 372, 394, 405, 457, 501, 549, 646, 648, 681, 714, 720, 967, 976, 1158, 1166, 1257, 1276, 1340, 1386, 1674, 1865, 1867, 1876, 1877, 1880, 1883, 1919, 1925, 1931, 2141, 2171, 3276, 3290, 3291, 3306, 3307, 3308, 3573, 3619, 3622, 3637, 3711, 4557, 5155, 5156, 5797, 5799, 5800, 6120, 6663, and 6664.